Multiple voltage divider



Nov. 21, 1939.

H BAHRING MULTIPLE VOLTAGE'DIVIDER Filed March 3, 1938 Patented Nov. 21, 1939 MULTIPLE VOLTAGE DIVIDER Herbert Bahrlng, Berlin-Zehlendori-Mitte, Germany, alaignor to the iirm of Fernseh Aktiengeaellschait, Zehlendori, near Berlin, Germany Application March 3, 1938, Serial No. 193,801

Germany March 3, 1937 3 Claims.

This invention relates to voltage dividers and particularly to multiple voltage dividers, by means of which a plurality of diiierent voltages can be developed and altered in certain relations to one another.

In measuring and control apparatus in the high frequency transmitting and receiving art, as well as in broadcasting and television receivers, the problem is often encountered to vary two or more voltages in relation to each other through ranges of diflerent magnitude and of diiierent percentage of variation by operating one control alone, whereby the variation may be required to be linear, in the same sense, or in the opposite sense.

It is known in the art, to use, for this purpose, one or a plurality of potentiometers with the desired ranges, and to couple these with a main potentiometer so that all sliding contacts are moved simultaneously. In many cases, however, such an arrangement is undesirable because the arrangement of several potentiometers on one axis causes spatial difflculties, and also requires careful mechanical adjustment.

It is the object of the present invention to provide a purely electrical arrangement in which the adjustment of one potentiometer alone causes the variation oi. a plurality of voltages as may be desired, for example, in linear relation to each other, in the same sense or in the opposite sense. According to the invention, the voltage to be varied simultaneously with a main voltage is developed across a voltage divider and a constant voltage source, which are both connected in series relation between the sliding tap or voltage adjusting means 01' the main voltage divider and one terminal of the main voltage source. In order to vary simultaneously a plurality of voltages through ranges of diflerent magnitudes and at different rates by the operation oi. one control element only, this invention provides certain rules, which will be set forth in the following, particularly in connection with Fig. 1 of the drawing.

Figure 1 is one modification of the apparatus which is the subject matter of this invention, while Figure 2 is a second modification of the invention.

Fig. 1 shows the principle of the circuit. Voltage U is applied at the points I and 2. The variable voltages U0, U1 and U: are taken off at the points 3 and I, 3 and 5 and 3 and 6, respectively. The main voltage divider consists of the resistances I and 8. Voltage U0 is adjusted to a desired value by means of the sliding contact 9 on the resistance I. The tap 9 is connected to a resistance Ill of the value R'1, and a resistance ll of the value R'a, which together constitute a fixed voltage divider with a tap 6. The additional voltage l2, provided in accordance with the invention, may have the value Uvz. Correspondingly, resistance l3 and H, with values R1 and R2 and a voltage source i5 01 the value Uvl are provided for the generation of volt- 8.88 U1.

If a change in the main voltage U0 from the value U01 to U0: is to cause the voltage U1 to change from the value U11 to U12, the following two equations must be fulfilled:

whereby, for instance, the sum. of R1+Rz may be chosen as may seem suitable. The value for R1 can then be computed from the equation If, for instance, the voltage between points 3 and G is to be varied between 376 and 600 volts, the voltage between points 3 and t5 varied between 3 and 20 volts, and the voltage between points 3 and 6 varied between and volts, it is necessary that Uvi=26.3 volts in accordance with Equation I. Assuming a value of R1+Rz=l megohm, Equation I yields Rz=74,000 ohms, and R1=926,000 ohms. From Equations I and 11' the following values are derived: Uv2=+25-0 volts, R'2=130,0O0 ohms and R'1=870,000 ohms.

In Fig. 2 a circuit is shown in which the voltage between points 4 and I6 is varied in the opposite sense to the variation of the voltages between the points 3 and 4, 22 and =3, 23 and 4. The maximum bias voltage lies between sliding contacts 9 and II, which are held at a constant distance from each other. A voltage divider I 9, 20, 2| develops the required constant bias voltages for the individual voltage dividers. The voltage U; between points 4 and I8 varies in the same sense as the voltage between the points 4 and is.

This method of multiple voltage control by means of one potentiometer alone is applicable, for instance, to scanning wave generators for television transmitting and receiving tubes for amplitude variation independent of frequency. The plate and grid voltages of the scanning wave generating discharge tube can be varied through ranges of different magnitudes, as well as through ranges of diflerent percentages or variation.

I claim: I

1., A circuit for simultaneous variation of a plurality oi voltages through ranges or dillerent magnitude and o! diflerent percentage of variation by operation of one control element only, comprising a variable voltage-divider possessing a tap, means tor producing a voltage drop between the tap and one terminal of said voltagedivider, means for applying said voltage to a work circuit, a series combination of a source of substantially constant voltage and a fixed voltagedivlder possessing a tap, said series combination being shunted across said variable voltage-divider between. the tap thereof and said terminal, and means for applying the voltage produced between the tap of said fixed voltage-divider and said terminal of said variable voltage-divider to am other trorlr circuit.

2.1%, circuit for the simultaneous variation of a plurality of voltages through ranges of different magnitude and at diflerent rates by the operation of one control element calm-comprising a potentiometer including voltage adjusting means, a source of substantially constant potential in series with another potentiometer having a plurality of sections of fixed value and a tap intermediate two of said sections, said source of potential and said potentiometer in series therewith being connected in shunt to a portion of said first mentioned potentiometer between said voltage adjusting means and another point at a different voltage value with respect thereto, and means enabling connection of work circuits between said adjustable voltage means and said other point, and between said tap and said other point.

3. A circuit for the simultaneous variation of a plurality of voltages through ranges of different magnitude and at different rates by the operation or one control element only, comprising a potentiometer including voltage adjusting means, a source of substantially constant potential U in series with a potentiometer of an overall arbitrary value having a pair or resistance sections i and FL- m 02 01 where U and U02 are desired changes in the potential across the adjustable potentiometer, U11 and U12 are the corresponding changes in potential desired across the resistor R2 and said source of potential Uu.

HERBERT BKHRING. 

